But there's a special historical pivot point in the twentieth century. It was the time of the acknowledgment of space. The great mass of humanity up until then had ignored, even then they knew of it, the size of the universe outside Earths air envelope and the insignificance of their little planet compared to it. Suddenly, they couldnt do that anymore, and the psychological shock was profound. Earth had suddenly ceased to be safe, warm protective shell for the race. They were suddenly naked to the stars. The shock of that made their century unique in human history and pre-history, and they were forced to be aware of the uniqueness. I know ” to those people who live in it, their own time is always the supremely important one; but the people in the twentieth really had some reason to think that way. The idea of space shook them up hard, down to the unconscious levels; and consequently, it shook up the then-existing forms of society – all-over Old Earth It cant be explained ” in the same sense as mathematics cant be explained ” in words. You have to talk the language in which it exist to explain it ” and even before that, your mind has to begin making the quantum jump to a first understanding of that language, before you really start learning what it is.